Detergent composition for use with a cleaning implement comprising a superabsorbent material and kits comprising both

ABSTRACT

A detergent composition for use with a cleaning pad comprising an effective amount of a superabsorbent material, said pad preferably being part of a cleaning implement comprising a handle and said cleaning pad preferably being removable. The detergent composition contains a limited amount of a detergent surfactant, preferably linear in structure and relatively hydrophilic, the level of hydrophobic materials being kept below about 0.5%, and the pH being maintained above about 9, to allow the superabsorbent material to be readily absorbed by the superabsorbent material. The process of using the detergent composition with such a cleaning pad, and the provision of a kit containing both detergent composition and cleaning pad are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a 371 of International ApplicationPCT/IB98/00356, with an international filing date of Mar. 16, 1998,which claims the benefit of U.S. Provisional Application Ser. No.60/041,273 filed Mar. 20, 1997 and Ser. No. 60/045,858 filed May 8,1997.

TECHNICAL FIELD

This application relates to detergent compositions for use with acleaning implement comprising a superabsorbent material useful inremoving soils from hard surfaces. The application particularly relatesto cleaning implements comprising a removable absorbent cleaning pad,preferably designed so as to provide multiple cleaning surfaces.

BACKGROUND OF THE INVENTION

The literature is replete with products capable of cleaning hardsurfaces such as ceramic tile floors, hardwood floors, counter tops andthe like. In the context of cleaning floors, numerous devices aredescribed comprising a handle and some means for absorbing a fluidcleaning composition. Such devices include those that are reusable,including mops containing cotton strings, cellulose and/or syntheticstrips, sponges, and the like. While these mops are successful inremoving many soils from hard surfaces, they typically require theinconvenience of performing one or more rinsing steps during use toavoid saturation of the material with dirt, soil, and other residues.These mops therefore require the use of a separate container to performthe rinsing step(s), and typically these rinsing steps fail tosufficiently remove dirt residues. This may result in redeposition ofsignificant amounts of soil during subsequent passes of the mop.Furthermore, as reusable mops are used over time, they becomeincreasingly soiled and malodorous. This negatively impacts subsequentcleaning performance.

To alleviate some of the negative attributes associated with reusablemops, attempts have been made to provide mops having disposable cleaningpads. For example, U.S. Pat. No. 5,094,559, issued Mar. 10, 1992 toRiviera et al., describes a mop that includes a disposable cleaning padcomprising a scrubber layer for removing soil from a soiled surface, ablotter layer to absorb fluid after the cleaning process, and a liquidimpervious layer positioned between the scrubber and blotter layer. Thepad further contains a rupturable packet means positioned between thescrubber layer and the liquid impervious layer. The rupturable packetsare so located such that upon rupture, fluid is directed onto thesurface to be cleaned. During the cleaning action with the scrubberlayer, the impervious sheet prevents fluid from moving to the absorbentblotter layer. After the cleaning action is completed, the pad isremoved from the mop handle and reattached such that the blotter layercontacts the floor. While this device may alleviate the need to usemultiple rinsing steps, it does require that the user physically handlethe pad and reattach a soiled, damp pad in order to complete thecleaning process.

Similarly, U.S. Pat. No. 5,419,015, issued May 30, 1995 to Garcia,describes a mop having removable, washable work pads. The pad isdescribed as comprising an upper layer which is capable of attaching tohooks on a mop head, a central layer of synthetic plastic microporousfoam, and a lower layer for contacting a surface during the cleaningoperation. The lower layer's composition is stated to depend on theend-use of the device, i.e., washing, polishing or scrubbing. While thereference addresses the problems associated with mops that requirerinsing during use, the patent fails to provide a cleaning implementthat sufficiently removes the soil deposited on typical household hardsurfaces, in particular floors, such that the surface is perceived asessentially free of soil. In particular, the synthetic foam described byGarcia for absorbing the cleaning solution has a relatively lowabsorbent capacity for water and water-based solutions. As such, theuser must either use small amounts of cleaning solution to remain withinthe absorbent capacity of the pad, or the user must leave a significantamount of cleaning solution on the surface being cleaned. In eithersituation, the overall performance of the cleaning pad is not optimal.

While many known devices for cleaning hard surfaces are successful atremoving a vast majority of the soil encountered by the typical consumerduring the cleaning process, they are inconvenient in that they requireone or more cleaning steps. The prior art devices that have addressedthe issue of convenience typically do so at the cost of cleaningperformance. As such, there remains a need for a device that offers bothconvenience and beneficial soil removal.

Therefore, the present invention preferably provides a cleaningimplement that comprises a removable cleaning pad, which alleviates theneed to rinse the pad during use. This requires an implement thatcomprises a removable cleaning pad with sufficient absorbent capacity,on a gram of absorbed fluid per gram of cleaning pad basis, that allowsthe cleaning of a large area, such as that of the typical hard surfacefloor (e.g., 80-100 ft²), without the need to change the pad. This, inturn, requires the use of a superabsorbent material, preferably of thetype disclosed hereinafter. It has now been found that the detergentcomposition that is used with such superabsorbent matierials must becarefully formulated to avoid defeating the goal of using suchsuperabsorbent material.

The preferred cleaning implements have a pad which offers beneficialsoil removal properties due to continuously providing a fresh surface,and/or edge to contact the soiled surface, e.g., by provideng aplurality of surfaces that contact the soiled surface during thecleaning operation.

SUMMARY OF THE INVENTION

Detergent compositions which are to be used with an implement containinga superabsorbent material require sufficient detergent to enable thesolution to provide cleaning without overloading the superabsorbentmaterial with solution, but cannot have more than about 0.5% detergentsurfactant without the performance suffering. to Therefore, the level ofdetergent surfactant should be from about 0.01% to about 0.5%,preferably from about 0.1% to about 0.45%, more preferably from about0.2% to about 0.45%; the level of hydrophobic materials, includingsolvent, should be less than about 0.5%, preferably less than about0.2%, more preferably less than about 0.1%; and the pH should be morethan about 9, preferably more than about 9.5, more preferably more thanabout 10, to avoid hindering absorption, and the alkalinity shouldpreferably be provided, at least in part, by volatile materials, toavoid streaking/filming problems. The detergent surfactant is preferablypredominantly linear, e.g., aromatic groups should not be present, andthe detergent surfactant is preferably relatively water soluble, e.g.,having a hydrophobic chain containing from about 8 to about 12,preferably from about 8 to about 11, carbon atoms, and, for nonionicdetergent surfactants, having an HLB of from about 9 to about 14,preferably from about 10 to about 13, more preferably from about 10 toabout 12.

The invention also comprises a detergent composition as disclosed hereinin a container in association with instructions to use it with anabsorbent structure comprising an effective amount of a superabsorbentmaterial, and, optionally, in a container in a kit comprising theimplement, or, at least, a disposable cleaning pad comprising asuperabsorbent material.

The invention also relates to the use of the composition and a cleaningpad comprising a superabsorbent material to effect cleaning of soiledsurfaces, i.e., the process of cleaning a surface comprising applying aneffective amount of a detergent composition containing no more thanabout 1% detergent surfactant; a level of hydrophobic materials,including solvent, that is less than about 0.5%; and a pH of more thanabout 9 and absorbing the composition in an absorbent structurecomprising a superabsorbent material.

In one preferred aspect, the present invention relates to the use of thedescribed detergent composition with an implement for cleaning asurface, the implement comprising:

a. a handle; and

b. a removable cleaning pad comprising a superabsorbent material andhaving a plurality of substantially planar surfaces, wherein each of thesubstantially planar surfaces contacts the surface being cleaned, andpreferably a pad structure which has both a first layer and a secondlayer, wherein the first layer is located between the scrubbing layerand the second layer and has a smaller width than the second layer.

Depending on the means used for attaching the cleaning pad to thecleaning implement's handle, it may be preferable for the cleaning padto further comprise a distinct attachment layer. In these embodiments,the absorbent layer would be positioned between the scrubbing layer andthe attachment layer.

The detergent composition and, preferably, the implement of the presentinvention are compatible with all hard surface substrates, includingwood, vinyl, linoleum, no wax floors, ceramic, Formica®, porcelain,glass, wall board, and the like.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1a is a perspective view of a cleaning implement used with adetergent composition of the present invention which has an on-boardfluid dispensing device.

FIG. 1b is a perspective view of a cleaning implement used with adetergent composition of the present invention which does not have anon-board fluid dispensing device.

FIG. 2 is a perspective view of a cleaning pad used with a detergentcomposition of the present invention.

FIG. 3 is a perspective view of a cleaning pad used with a detergentcomposition of the present invention.

FIG. 4 is a blown perspective view of the absorbent layer of a cleaningpad used with a detergent composition of the present invention.

FIG. 5a is a plan view of a cleaning pad used with a detergentcomposition of the present invention.

FIG. 5b is a cross sectional view of the cleaning pad shown in FIG. 5a.

FIG. 6 represents a schematic view of an apparatus for measuring thePerformance Under Pressure (PUP) capacity of a cleaning pad used with adetergent composition of the present invention.

FIG. 7 represents an enlarged sectional view of the piston/cylinderassembly shown in FIG. 6.

DETAILED DESCRIPTION

I. The Cleaning Pad

The present invention is based on providing the convenience of acleaning pad, preferably removable and/or disposable, that contains asuperabsorbent material and which preferably also provides significantcleaning benefits. The preferred cleaning performance benefits arerelated to the preferred structural characteristics described below,combined with the ability of the pad to remove solubilized soils. Thecleaning pad, as described herein requires the use of the detergentcomposition, as described hereinafter, to provide optimum performance.

The cleaning pads will preferably have an absorbent capacity whenmeasured under a confining pressure of 0.09 psi after 20 minutes (1200seconds) (hereafter refered to as “t₁₂₀₀ absorbent capacity”) of atleast about 10 g deionized water per g of the cleaning pad. Theabsorbent capacity of the pad is measured at 20 minutes (1200 seconds)after exposure to deionized water, as this represents a typical time forthe consumer to clean a hard surface such as a floor. The confiningpressure represents typical pressures exerted on the pad during thecleaning process. As such, the cleaning pad should be capable ofabsorbing significant amounts of the cleaning solution within this 1200second period under 0.09 psi. The cleaning pad will preferably have at₁₂₀₀ absorbent capacity of at least about 15 g/g, more preferably atleast about 20 g/g, still more preferably at least about 25 gig and mostpreferably at least about 30 g/g. The cleaning pad will preferably havea t₉₀₀ absorbent capacity of at least about 10 g/g, more preferably at₉₀₀ absorbent capacity of at least about 20 g/g.

Values for t₁₂₀₀ and t₉₀₀ absorbent capacity are measured by theperformance under pressure (referred to herein as “PUP”) method, whichis described in detail in the Test Methods section below.

The cleaning pads will also preferably, but not necessarily, have atotal fluid capacity (of deionized water) of at least about 100 g, morepreferably at least about 200 g, still more preferably at least about300 g and most preferably at least about 400 g. While pads having atotal fluid capacity less than 100 g are within the scope of theinvention, they are not as well suited for cleaning large areas, such asseen in a typical household, as are higher capacity pads.

Each of the components of the absorbent pad are described in detail.However, the skilled artisan will recognize that various materials knownto serve similar purposes may substituted with similar results.

A. Absorbent Layer

The absorbent layer is the essential component which serves to retainany fluid and soil absorbed by the cleaning pad during use. While thepreferred scrubbing layer, described hereinafter, has some affect on thepad's ability to absorb fluid, the absorbent layer plays the major rolein achieving the desired overall absorbency. Furthermore, the absorbentlayer preferably comprises multiple layers which are designed to providethe cleaning pad with multiple planar surfaces.

From the essential fluid absorbency perspective, the absorbent layerwill be capable of removing fluid and soil from any “scrubbing layer” sothat the scrubbing layer will have capacity to continually remove soilfrom the surface. The absorbent layer also should be capable ofretaining absorbed material under typical in-use pressures to avoid“squeeze-out” of absorbed soil, cleaning solution, etc.

The absorbent layer will comprise any material that is capable ofabsorbing and retaining fluid during use. To achieve desired total fluidcapacities, it will be preferred to include in the absorbent layer amaterial having a relatively high capacity (in terms of grams of fluidper gram of absorbent material). As used herein, the term“superabsorbent material” means any absorbent material having a g/gcapacity for water of at least about 15 g/g, when measured under aconfining pressure of 0.3 psi. Because a majority of the cleaning fluidsuseful with the present invention are aqueous based, it is preferredthat the superabsorbent materials have a relatively high g/g capacityfor water or water-based fluids.

Representative superabsorbent materials include water insoluble,water-swellable superabsorbent gelling polymers (referred to herein as“superabsorbent gelling polymers”) which are well known in theliterature. These materials demonstrate very high absorbent capacitiesfor water. The superabsorbent gelling polymers useful in the presentinvention can have a size, shape and/or morphology varying over a widerange. These polymers can be in the form of particles that do not have alarge ratio of greatest dimension to smallest dimension (e.g., granules,flakes, pulverulents, interparticle aggregates, interparticlecrosslinked aggregates, and the like) or they can be in the form offibers, sheets, films, foams, laminates, and the like. The use ofsuperabsorbent gelling polymers in fibrous form provides the benefit ofproviding enhanced retention of the superabsorbent material, relative toparticles, during the cleaning process. While their capacity isgenerally lower for aqueous-based mixtures, these materials stilldemonstate significant absorbent capacity for such mixtures. The patentliterature is replete with disclosures of water-swellable materials.See, for example, U.S. Pat. No. 3,699,103 (Harper et al.), issued Jun.13, 1972; U.S. Pat. No. 3,770,731 (Harmon), issued Jun. 20, 1972; U.S.

Reissue Pat. No. 32,649 (Brandt et al.), reissued Apr. 19, 1989; U.S.Pat. No. 4,834,735 (Alemany et al.), issued May 30, 1989.

Superabsorbent gelling polymers useful in the present invention includea variety of water-insoluble, but water-swellable polymers capable ofabsorbing large quantities of fluids. Such polymeric materials are alsocommonly referred to as “hydrocolloids”, and can include polysaccharidessuch as carboxymethyl starch, carboxymethyl cellulose, and hydroxypropylcellulose; nonionic types such as polyvinyl alcohol, and polyvinylethers; cationic types such as polyvinyl pyridine, polyvinylmorpholinione, and N,N-dimethylaminoethyl or N,N-diethylaminopropylacrylates and methacrylates, and the respective quaternary saltsthereof. Typically, superabsorbent gelling polymers useful in thepresent invention have a multiplicity of anionic functional groups, suchas sulfonic acid, and more typically carboxy, groups. Examples ofpolymers suitable for use herein include those which are prepared frompolymerizable, unsaturated, acid-containing monomers. Thus, suchmonomers include the olefinically unsaturated acids and anhydrides thatcontain at least one carbon to carbon olefinic double bond. Morespecifically, these monomers can be selected from olefinicallyunsaturated carboxylic acids and acid anhydrides, if olefinicallyunsaturated sulfonic acids, and mixtures thereof.

Some non-acid monomers can also be included, usually in minor amounts,in preparing the superabsorbent gelling polymers useful herein. Suchnon-acid monomers can include, for example, the water-soluble orwater-dispersible esters of the acid-containing monomers, as well asmonomers that contain no carboxylic or sulfonic acid groups at all.Optional non-acid monomers can thus include monomers containing thefollowing types of functional groups: carboxylic acid or sulfonic acidesters, hydroxyl groups, amide-groups, amino groups, nitrile groups,quaternary ammonium salt groups, aryl groups (e.g., phenyl groups, suchas those derived from styrene monomer). These non-acid monomers arewell-known materials and are described in greater detail, for example,in U.S. Pat. No. 4,076,663 (Masuda et al), issued Feb. 28, 1978, and inU.S. Pat. No. 4,062,817 (Westerman), issued Dec. 13, 1977, both of whichare incorporated by reference.

Olefinically unsaturated carboxylic acid and carboxylic acid anhydridemonomers include the acrylic acids typified by acrylic acid itself,methacrylic acid, ethacrylic acid, α-chloroacrylic acid, a-cyanoacrylicacid, β-methylacrylic acid (crotonic acid), α-phenylacrylic acid,β-acryloxypropionic acid, sorbic acid, α-chlorosorbic acid, angelicacid, cinnamic acid, p-chlorocinnamic acid, β-sterylacrylic acid,itaconic acid, citroconic acid, mesaconic acid, glutaconic acid,aconitic acid, maleic acid, fumaric acid, tricarboxyethylene and maleicacid anhydride.

Olefinically unsaturated sulfonic acid monomers include aliphatic oraromatic vinyl sulfonic acids such as vinylsulfonic acid, allyl sulfonicacid, vinyl toluene sulfonic acid and styrene sulfonic acid; acrylic andmethacrylic sulfonic acid such as sulfoethyl acrylate, sulfoethylmethacrylate, sulfopropyl acrylate, sulfopropyl methacrylate,2-hydroxy-3-methacryloxypropyl sulfonic acid and2-acrylamide-2-methylpropane sulfonic acid.

Preferred superabsorbent gelling polymers for use in the presentinvention contain carboxy groups. These polymers include hydrolyzedstarch-acrylonitrile graft copolymers, partially neutralized hydrolyzedstarch-acrylonitrile graft copolymers, starch-acrylic acid graftcopolymers, partially neutralized starch-acrylic acid graft copolymers,saponified vinyl acetate-acrylic ester copolymers, hydrolyzedacrylonitrile or acrylamide copolymers, slightly network crosslinkedpolymers of any of the foregoing copolymers, partially neutralizedpolyacrylic acid, and slightly network crosslinked polymers of partiallyneutralized polyacrylic acid. These polymers can be used either solelyor in the form of a mixture of two or more different polymers. Examplesof these polymer materials are disclosed in U.S. Pat. Nos. 3,661,875,4,076,663, 4,093,776, 4,666,983, and 4,734,478.

Most preferred polymer materials for use in making the superabsorbentgelling polymers are slightly network crosslinked polymers of partiallyneutralized polyacrylic acids and starch derivatives thereof. Mostpreferably, the hydrogel-forming absorbent polymers comprise from about50 to about 95%, preferably about 75%, neutralized, slightly networkcrosslinked, polyacrylic acid (i.e. poly (sodium acrylate/acrylicacid)). Network crosslinking renders the polymer substantiallywater-insoluble and, in part, determines the absorptive capacity andextractable polymer content characteristics of the superabsorbentgelling polymers. Processes for network crosslinking these polymers andtypical network crosslinking agents are described in greater detail inU.S. Pat. No. 4,076,663.

While the superabsorbent gelling polymers is preferably of one type(i.e., homogeneous), mixtures of polymers can also be used in theimplements of the present invention. For example, mixtures ofstarch-acrylic acid graft copolymers and slightly network crosslinkedpolymers of partially neutralized polyacrylic acid can be used in thepresent invention.

While any of the superabsorbent gelling polymers described in the priorart may be useful in the present invention, it has recently beenrecognized that where significant levels (e.g., more than about 50% byweight of the absorbent structure) of superabsorbent gelling polymersare to be included in an absorbent structure, and in particular whereone or more regions of the absorbent layer will comprise more than about50%, by weight of the region, the problem of gel blocking by the swollenparticles may impede fluid flow and thereby adversely affect the abilityof the gelling polymers to absorb to their full capacity in the desiredperiod of time. U.S. Pat. No. 5,147,343 (Kellenberger et al.), issuedSep. 15, 1992 and U.S. Pat. No. 5,149,335 (Kellenberger et al.), issuedSep. 22, 1992, describe superabsorbent gelling polymers in terms oftheir Absorbency Under Load (AUL), where gelling polymers absorb fluid(0.9% saline) under a confining pressure of 0.3 psi. (The disclosure ofeach of these patents is incorporated herein.) The methods fordetermining AUL are described in these patents. Polymers describedtherein may be particularly useful in embodiments of the presentinvention that contain regions of relatively high levels ofsuperabsorbent gelling polymers. In particular, where highconcentrations of superabsorbent gelling polymer are incorporated in thecleaning pad, those polymers will preferably have an AUL, measuredaccording to the methods described in U.S. Pat. No. 5,147,343, of atleast about 24 ml/g, more preferably at least about 27 ml/g after 1hour; or an AUL, measured according to the methods described in U.S.Pat. No. 5,149,335, of at least about 15 ml/g, more preferably at leastabout 18 ml/g after 15 minutes. Commonly assigned copending U.S.application Ser. No. 08/219,574 (Goldman et al.), filed Mar. 29, 1994now U.S. Pat. No. 5,599,335 and 08/416,396 (Goldman et al.), filed Apr.6, 1995 now U.S. Pat. No. 5,562,646 (both of which are incorporated byreference herein), also address the problem of gel blocking and describesuperabsorbent gelling polymers useful in overcoming this phenomena.These applications specifically describe superabsorbent gelling polymerswhich avoid gel blocking at even higher confining pressures,specifically 0.7 psi. In the embodiments of the present invention wherethe absorbent layer will contain regions comprising high levels (e.g.,more than about 50% by weight of the region) of superabsorbent gellingpolymer, it may be preferred that the superabsorbent gelling polymer beas described in the aforementioned applications by Goldman et al.

Other useful superbsorbent materials include hydrophilic polymericfoams, such as those described in commonly assigned copending U.S.patent application Ser. No. 08/563,866 (DesMarais et al.), filed Nov.29, 1995 now U.S. Pat. No. 5,650,222 and U.S. Pat. No. 5,387,207 (Dyeret al.), issued Feb. 7, 1995. These references describe polymeric,hydrophilic absorbent foams that are obtained by polymerizing a highinternal phase water-in-oil emulsion (commonly referred to as HIPEs).These foams are readily taylored to provide varying physical properties(pore size, capillary suction, density, etc.) that affect fluid handlingability. As such, these materials are particularly useful, either aloneor in combination with other such foams or with fibrous structures, inproviding the overall capacity required by the present invention.

Where superabsorbent material is included in the absorbent layer, theabsorbent layer will preferably comprise at least about 15%, by weightof the absorbent layer, more preferably at least about 20%, still morepreferably at least about 25%, of the superabsorbent material.

The absorbent layer may also consist of or comprise fibrous material.Fibers useful in the present invention include those that are naturallyoccurring (modified or unmodified), as well as synthetically madefibers. Examples of suitable unmodified/modified naturally occurringfibers include cotton, Esparto grass, bagasse, kemp, flax, silk, wool,wood pulp, chemically modified wood pulp, jute, ethyl cellulose, andcelluloseacetate. Suitable synthetic fibers can be made from ispolyvinyl chloride, polyvinyl fluoride, polytetrafluoroethylene,polyvinylidene chloride, polyacrylics such as ORLON®, polyvinyl acetate,Rayon®, polyethylvinyl acetate, non-soluble or soluble polyvinylalcohol, polyolefins such as polyethylene (e.g., PULPEX®) andpolypropylene, polyamides such as nylon, polyesters such as DACRON® orKODEL®, polyurethanes, polystyrenes, and the like. The absorbent layercan comprise solely naturally occurring fibers, solely synthetic fibers,or any compatible combination of naturally occurring and syntheticfibers.

The fibers useful herein can be hydrophilic, hydrophobic or can be acombination of both hydrophilic and hydrophobic fibers. As indicatedabove, the particular selection of hydrophilic or hydrophobic fiberswill depend upon the other materials included in the absorbent (and tosome degree the scrubbing) layer. That is, the nature of the fibers willbe such that the cleaning pad exhibits the necessary fluid delay andoverall fluid absorbency. Suitable hydrophilic fibers for use in thepresent invention include cellulosic fibers, modified cellulosic fibers,rayon, polyester fibers such as hydrophilic nylon (HYDROFIL®). Suitablehydrophilic fibers can also be obtained by hydrophilizing hydrophobicfibers, such as surfactant-treated or silica-treated thermoplasticfibers derived from, for example, polyolefins such as polyethylene orpolypropylene, polyacrylics, polyamides, polystyrenes, polyurethanes andthe like.

Suitable wood pulp fibers can be obtained from well-known chemicalprocesses such as the Kraft and sulfite processes. It is especiallypreferred to derive these wood pulp fibers from southern soft woods dueto their premium absorbency characteristics. These wood pulp fibers canalso be obtained from mechanical processes, such as ground wood, refinermechanical, thermomechanical, chemimechanical, andchemi-thermomechanical pulp processes. Recycled or secondary wood pulpfibers, as well as bleached and unbleached wood pulp fibers, can beused.

Another type of hydrophilic fiber for use in the present invention ischemically stiffened cellulosic fibers. As used herein, the term“chemically stiffened cellulosic fibers” means cellulosic fibers thathave been stiffened by chemical means to increase the stiffness of thefibers under both dry and aqueous conditions. Such means can include theaddition of a chemical stiffening agent that, for example, coats and/orimpregnates the fibers. Such means can also include the stiffening ofthe fibers by altering the chemical structure, e.g., by crosslinkingpolymer chains.

Where fibers are used as the absorbent layer (or a constituent componentthereof), the fibers may optionally be combined with a thermoplasticmaterial. Upon melting, at least a portion of this thermoplasticmaterial migrates to the intersections of the fibers, typically due tointerfiber capillary gradients. These intersections become bond sitesfor the thermoplastic material. When cooled, the thermoplastic materialsat these intersections solidify to form the bond sites that hold thematrix or web of fibers together in each of the respective layers. Thismay be beneficial in providing additional overall integrity to thecleaning pad.

Amongst its various effects, bonding at the fiber intersectionsincreases the overall compressive modulus and strength of the resultingthermally bonded member. In the case of the chemically stiffenedcellulosic fibers, the melting and migration of the thermoplasticmaterial also has the effect of increasing the average pore size of theresultant web, while maintaining the density and basis weight of the webas originally formed. This can improve the fluid acquisition propertiesof the thermally bonded web upon initial exposure to fluid, due toimproved fluid permeability, and upon subsequent exposure, due to thecombined ability of the stiffened fibers to retain their stiffness uponwetting and the ability of the thermoplastic material to remain bondedat the fiber intersections upon wetting and upon wet compression. Innet, thermally bonded webs of stiffened fibers retain their originaloverall volume, but with the volumetric regions previously occupied bythe thermoplastic material becoming open to thus increase the averageinterfiber capillary pore size.

Thermoplastic materials useful in the present invention can be in any ofa variety of forms including particulates, fibers, or combinations ofparticulates and fibers. Thermoplastic fibers are a particularlypreferred form because of their ability to form numerous interfiber bondsites. Suitable thermoplastic materials can be made from anythermoplastic polymer that can be melted at temperatures that will notextensively damage the fibers that comprise the primary web or matrix ofeach layer. Preferably, the melting point of this thermoplastic materialwill be less than about 190° C., and preferably between about 75° C. andabout 175° C. In any event, the melting point of this thermoplasticmaterial should be no lower than the temperature at which the thermallybonded absorbent structures, when used in the cleaing pads, are likelyto be stored. The melting point of the thermoplastic material istypically no lower than about 50° C.

The thermoplastic materials, and in particular the thermoplastic fibers,can be made from a variety of thermoplastic polymers, includingpolyolefins such as polyethylene (e.g., PULPEX®) and polypropylene,polyesters, copolyesters, polyvinyl acetate, polyethylvinyl acetate,polyvinyl chloride, polyvinylidene chloride, polyacrylics, polyamides,copolyamides, polystyrenes, polyurethanes and copolymers of any of theforegoing such as vinyl chloride/vinyl acetate, and the like. Dependingupon the desired characteristics for the resulting thermally bondedabsorbent member, suitable thermoplastic materials include hydrophobicfibers that have been made hydrophilic, such as surfactant-treated orsilica-treated thermoplastic fibers derived from, for example,polyolefins such as polyethylene or polypropylene, polyacrylics,polyamides, polystyrenes, polyurethanes and the like. The surface of thehydrophobic thermoplastic fiber can be rendered hydrophilic by treatmentwith a surfactant, such as a nonionic or anionic surfactant, e.g., byspraying the fiber with a surfactant, by dipping the fiber into asurfactant or by including the surfactant as part of the polymer melt inproducing the thermoplastic fiber. Upon melting and resolidification,the surfactant will tend to remain at the surfaces of the thermoplasticfiber. Suitable surfactants include nonionic surfactants such as Brij®76 manufactured by ICI Americas, Inc. of Wilmington, Del., and varioussurfactants sold under the Pegosperse® trademark by Glyco Chemical, Inc.of Greenwich, Conn. Besides nonionic surfactants, anionic surfactantscan also be used. These surfactants can be applied to the thermoplasticfibers at levels of, for example, from about 0.2 to about 1 g. per sq.of centimeter of thermoplastic fiber.

Suitable thermoplastic fibers can be made from a single polymer(monocomponent fibers), or can be made from more than one polymer (e.g.,bicomponent fibers). As used herein, “bicomponent fibers” refers tothermoplastic fibers that comprise a core fiber made from one polymerthat is encased within a thermoplastic sheath made from a differentpolymer. The polymer comprising the sheath often melts at a different,typically lower, temperature than the polymer comprising the core. As aresult, these bicomponent fibers provide thermal bonding due to meltingof the sheath polymer, while retaining the desirable strengthcharacteristics of the core polymer.

Suitable bicomponent fibers for use in the present invention can includesheath/core fibers having the following polymer combinations:polyethylene/ polypropylene, polyethylvinyl acetate/polypropylene,polyethylene/polyester, polypropylene/polyester, copolyester/polyester,and the like. Particularly suitable bicomponent thermoplastic fibers foruse herein are those having a polypropylene or polyester core, and alower melting copolyester, polyethylvinyl acetate or polyethylene sheath(e.g., those available from Danaklon a/s, Chisso Corp., and CELBOND®,available from Hercules). These bicomponent fibers can be concentric oreccentric. As used herein, the terms “concentric” and “eccentric” referto whether the sheath has a thickness that is even, or uneven, throughthe cross-sectional area of the bicomponent fiber. Eccentric bicomponentfibers can be is desirable in providing more compressive strength atlower fiber thicknesses.

Methods for preparing thermally bonded fibrous materials are describedin U.S. application Ser. No. 08/479,096 (Richards et al.), filed Jul. 3,1995 now U.S. Pat. Nos. 5,607,414 and 5,549,589 (Horney et al.), issuedAug. 27, 1996 (see especially Columns 9 to 10). The disclosure of bothof these references are incorporated by reference herein.

The absorbent layer may also comprise a HIPE-derived hydrophilic,polymeric foam that does not have the high absorbency of those describedabove as “superabsorbent materials”. Such foams and methods for theirpreparation are described in U.S. Pat. No. 5,550,167 (DesMarais), issuedAug. 27, 1996; and commonly assigned U.S. patent application Ser. No.08/370,695 (Stone et al.), filed Jan. 10, 1995 now U.S. Pat. No.5,563,179 (both of which are incorporated by reference herein).

The absorbent layer of the cleaning pad may be comprised of ahomogeneous material, such as a blend of cellulosic fibers (optionablythermally bonded) and swellable superabsorbent gelling polymer.Alternatively, the absorbent layer may be comprised of discrete layersof material, such as a layer of thermally bonded airlaid material and adiscrete layer of a superabsorbent material. For example, a thermallybonded layer of cellulosic fibers can be located lower than (i.e.,beneath) the superabsorbent material (i.e., between the superabsorbentmaterial and the scrubbing layer). In order to achieve high absorptivecapacity and retention of fluids under pressure, while at the same timeproviding initial delay in fluid uptake, it may be preferable to utilizesuch discrete layers when forming the absorbent layer. In this regard,the superabsorbent material can be located remote from the scrubbinglayer by including a less absorbent layer as the lower-most aspect ofthe absorbent layer. For example, a layer of cellulosic fibers can belocated lower (i.e., beneath) than the superabsorbent material (i.e.,between the superabsorbent material and the scrubbing layer).

In a preferred embodiment, the absorbent layer will comprise a thermallybonded airlaid web of cellulose fibers (Flint River, available fromWeyerhaeuser, Wash.) and AL Thermal C (thermoplastic available fromDanaklon a/s, Varde, Denmark), and a swellable hydrogel-formingsuperabsorbent polymer. The superabsorbent polymer is preferablyincorporated such that a discrete layer is located near the surface ofthe absorbent layer which is remote from the scrubbing layer.Preferably, a thin layer of, e.g., cellulose fibers (optionallythermally bonded) are positioned above the superabsorbent gellingpolymer to enhance containment.

B. Optional, but Preferred, Scrubbing Layer

The scrubbing layer is the portion of the cleaning pad that contacts thesoiled surface during cleaning. As such, materials useful as thescrubbing layer must be sufficiently durable that the layer will retainits integrity during the cleaning process. In addition, when thecleaning pad is used in combination with a solution, the scrubbing layermust be capable of absorbing liquids and soils, and relinquishing thoseliquids and soils to the absorbent layer. This will ensure that thescrubbing layer will continually be able to remove additional materialfrom the surface being cleaned. Whether the implement is used with acleaning solution (i.e., in the wet state) or without cleaning solution(i.e., in the dry state), the scrubbing layer will, in addition toremoving particulate matter, facilitate other functions, such aspolishing, dusting, and buffing the surface being cleaned.

The scrubbing layer can be a monolayer, or a multi-layer structure oneor more of whose layers may be slitted to faciliate the scrubbing of thesoiled surface and the uptake of particulate matter. This scrubbinglayer, as it passes over the soiled surface, interacts with the soil(and cleaning solution when used), loosening and emulsifying tough soilsand permitting them to pass freely into the absorbent layer of the pad.The scrubbing layer preferably contains openings (e.g., slits) thatprovide an easy avenue for larger particulate soil to move freely in andbecome entrapped within the absorbent layer of the pad. Low densitystructures are preferred for use as the scrubbing layer, to facilitatetransport of particulate matter to the pad's absorbent layer.

In order to provide desired integrity, materials particularly suitablefor the scrubbing layer include synthetics such as polyolefins (e.g.,polyethylene and polypropylene), polyesters, polyamides, syntheticcellulosics (e.g., Rayon®), and blends thereof. Such synthetic materialsmay be manufactured using known process such as carded, spunbond,meltblown, airlaid, needlepunched and the like.

C. Optional Attachment Layer

The cleaning pads of the present invention can optionally have anattachment layer that allows the pad to be connected to an implement'shandle or the support head in preferred implements. The attachment layerwill be necessary in those embodiments where the absorbent layer is notsuitable for attaching the pad to the support head of the handle. Theattachment layer may also function as a means to prevent fluid flowthrough the top surface (i.e., the handle-contacting surface) of thecleaning pad, and may further provide enhanced integrity of the pad. Aswith the scrubbing and absorbent layers, the attachment layer mayconsist of a mono-layer or a multi-layer structure, so long as it meetsthe above requirements.

In a preferred embodiment of the present invention, the attachment layerwill comprise a surface which is capable of being mechanically attachedto the handle's support head by use of known hook and loop technology.In such an embodiment, the attachment layer will comprise at least onesurface which is mechanically attachable to hooks that are permanentlyaffixed to the bottom surface of the handle's support head.

To achieve the desired fluid imperviousness and attachability, it ispreferred that a laminated structure comprising, e.g., a meltblown filmand fibrous, nonwoven structure be utilized. In a preferred embodiment,the attachment layer is a tri-layered material having a layer ofmeltblown polypropylene film located between two layers of spun-bondedpolypropylene.

D. Optional but Preferred, Multiple Planar Surfaces

While the ability of the cleaning pad to absorb and retain fluids hasbeen determined to be important to hard surface cleaning performance(see, e.g., U.S. patent application Ser. No. 08/756,507 (Holt et al.),now U.S. Pat. No. 5,960,508 copending U.S. patent application Ser. No.08/756,864 (Sherry et al.) now U.S. Pat. No. 6,003,191, and copendingU.S. patent application Ser. No. 08/756,999 (Holt et al.) now U.S. Pat.No. 6,048,123, all filed Nov. 26, 1996 and incorporated by referenceherein.), preferred performance can be achieved by properly defining theoverall structure of the cleaning pad. In particular, pads having anessentially flat floor contacting surface (i.e., essentially one planarsurface for contacting the soiled surface during cleaning) do notprovide the best performance because soil tends to build up on theleading edge, which also is the main point where the cleaning solutionis transferred to the absorbent layer.

The preferred pads provide multiple planar surfaces during cleaning andprovide enhanced performance. Referring to FIG. 2 in the drawings,cleaning pad 100 is depicted as having an upper surface 103 that allowsthe pad to be releasably attached to a handle. Cleaning pad 100 also hasa lower surface depicted generally as 110 which contacts the floor orother hard surface during cleaning. This lower surface 110 actuallyconsists of 3 substantially planar surfaces 112, 114 and 116. Asdepicted, the planes corresponding to surfaces 112 and 116 intersect theplane corresponding to surface 114. Thus, when an implement to which pad100 is attached is moved from rest in the direction indicated by Y_(f),friction causes pad 100 to “rock” such that lower surface 112 contactsthe surface being cleaned. As the movement in the Y_(f) directiondiminishes, lower surface 114 will then contact the surface beingcleaned. As the implement and pad are moved from rest in the Y_(b)direction, friction causes pad 100 to rock such that lower surface 116then contacts the surface being cleaned. As this cleaning motion isrepeated, the portion of the pad contacting the soiled surface areconstantly changing.

Applicants believe that the enhanced cleaning of the preferred pads isin-part due to the “lifting” action that results from the back and forthmotion during cleaning. In particular, when the cleaning motion in onedirection is stopped and the forces exerted on the implement allow pad100 to “rock” such that the surface-contacting planar surface moves fromsurface 112 (or 116) to surface 114, soil is moved in an an upwarddirection.

The cleaning pad of the present invention should be capable of retainingabsorbed fluid, even during the pressures exerted during the cleaningprocess. This is referred to herein as the cleaning pad's ability toavoid “squeeze-out” of absorbed fluid, or conversely its ability toretain absorbed fluid under pressure. The method for measuringsqueeze-out is described in the Test Methods section. Briefly, the testmeasures the ability of a saturated cleaning pad to retain fluid whensubjected to a pressure of 0.25 psi. Preferably, the cleaning pads ofthe present invention will have a squeeze-out value of not more thanabout 40%, more preferably not more than about 25%, still morepreferably not more than about 15%, and most preferably not more thanabout 10%.

II. Detergent Composition

The cleaning implement of the present invention is used in combinationwith a detergent composition which acts as a cleaning solution.Detergent compositions which are to be used with an implement containinga superabsorbent material require sufficient detergent to enable thesolution to provide cleaning without overloading the superabsorbentmaterial with solution, but cannot have more than about 0.5% detergentsurfactant without the performance suffering. Therefore, the level ofdetergent surfactant should be from about 0.01% to about 0.5%,preferably from about 0.1% to about 0.45%, more preferably from about0.2% to about 0.45%; the level of hydrophobic materials, includingsolvent, should be less than about 0.5%, preferably less than about0.2%, more preferably less than about 0.1%; and the pH should be morethan about 9.3, preferably more than about 10, more preferably more thanabout 10.3, to avoid hindering absorption, and the alkalinity shouldpreferably be provided, at least in part, by volatile materials, toavoid streaking/filming problems. The detergent surfactant is preferablylinear, e.g., branching and aromatic groups should not be present, andthe detergent surfactant is preferably relatively water soluble, e.g.,having a hydrophobic chain containing from about 8 to about 12,preferably from about 8 to about 11, carbon atoms, and, for nonionicdetergent surfactants, having an HLB of from about 9 to about 14,preferably from about 10 to about 13, more preferably from about 10 toabout 12. The invention also comprises a detergent composition asdisclosed herein in a container in association with instructions to useit with an implement comprising an effective amount of a superabsorbentmaterial, and, optionally, in a container in a kit comprising theimplement, or, at least, a disposable cleaning pad comprising asuperabsorbent material. The invention also relates to the use of thecomposition and a cleaning pad comprising a superabsorbent material toeffect cleaning of soiled surfaces.

The detergent composition, (cleaning solution) is an aqueous-basedsolution comprising one or more detergent surfactants, alkalinematerials to provide the desired alkaline pH, and optional solvents,builders, chelants, suds suppressors, enzymes, etc. Suitable surfactantsinclude anionic, nonionic, zwitterionic, and amphoteric surfactants,preferably anionic and nonionic detergent surfactants having hydrophobicchains containing from about 8 to about 12, preferably from about 8 toabout 11, carbon atoms. Examples of anionic surfactants include, but arenot limited to, linear alkyl sulfates, alkyl sulfonates, and the like.Examples of nonionic surfactants include alkylethoxylates and the like.Examples of zwitterionic surfactants include betaines and sulfobetaines.Examples of amphoteric surfactants include alkylampho glycinates, andalkyl imino propionate. All of the above materials are availablecommercially, and are described in McCutcheon's Vol. 1: Emulsifiers andDetergents, North American Ed., McCutheon Division, MC Publishing Co.,1995.

Suitable solvents include short chain (e.g., C₁-C₆) derivatives ofoxyethylene glygol and oxypropylene glycol, such as mono- anddi-ethylene glycol n-hexyl ether, mono-, di- and tri-propylene glycoln-butyl ether, and the like. The level of hydrophobic solvents, e.g.,those having solubilities in water of less than about 3%, morepreferably less than about 2%.

Suitable builders include those derived from phosphorous sources, suchas orthophosphate and pyrophosphate, and non-phosphorous sources, suchas nitrilotriacetic acid, S,S-ethylene diamine disuccinic acid, and thelike. Suitable chelants include ethylenediaminetetraacetic acid andcitric acid, and the like. Suitable suds suppressors include siliconepolymers and linear or branched C₁₀-C₁₈ fatty acids or alcohols.Suitable enzymes include lipases, proteases, amylases and other enzymesknown to be useful for catalysis of soil degradation. The total level ofsuch ingredients is low, preferably less than about 0.1%, morepreferably less than about 0.05%, to avoid causing filming streakingproblems. Preferably, the compositions should be essentially free ofmaterials that cause filming streaking problems. Accordingly, it isdesirable to use alkaline materials that do not cause filming and/orstreaking for the majority of the buffering. Suitable alkaline buffersare carbonate, bicarbonate, citrate, etc. The preferred alkaline buffersare alkanol amines having the formula:

CR₂(NH₂)CR₂OH

wherein each R is selected from the group consisting of hydrogen andalkyl groups containing from one to four carbon atoms and the total ofcarbon atoms in the compound is from three to six, preferably,2-amino,2-methylpropanol.

A suitable cleaning solution for use with the present implementcomprises from about 0.1% to about 0.5% of detergent surfactant,preferably comprising a linear alcohol ethoxylate detergent surfactant(e.g., Neodol 1-5®, available from Shell Chemical Co.) and analkylsulfonate (e.g., Bioterge PAS-8s, a linear C₈ sulfonate availablefrom Stepan Co.); from about 0 to about 0.2%, preferably from about0.05% to about 0.01, potassium hydroxide, potassium carbonate, and/orbicarbonate; from about 0.01% to about 1%, preferably from about 0.1% toabout 0.6%, of volatile alkaline material, e.g.,2-amino,2-methylpropanol; optional adjuvents such dyes and/or perfumes;and from about 99.9% to about 90% deionized or softened water.

II. Cleaning Implements

The detergent compositions described above can be desirably used with animplement for cleaning a surface, the implement comprising:

a. a handle; and

b. a removable cleaning pad containing an effective amount of asuperabsorbent material, and having a plurality of substantially planarsurfaces, wherein each of the substantially planar surfaces contacts thesurface being cleaned, more preferably said pad is a removable cleaningpad having a length and a width the pad comprising

i. a scrubbing layer; and

ii. an absorbent layer comprising a first layer and a second layer,where the first layer is located between the scrubbing layer and thesecond layer (i.e., the first layer is below the second layer) and has asmaller width than the second layer.

An important aspect of the cleaning performance provided by thepreferred to pad is related to the ability to provide multiple planarsurfaces that contact the soiled surface during the cleaning operation.In the context of a cleaning implement such as a mop, these planarsurfaces are provided such that during the typical cleaning operation(i.e., where the implement is moved back and forth in a directionsubstantially parallel to the pad's Y-dimension or width), each of theplanar surfaces contact the surface being cleaned as a result of“rocking” of the cleaning pad. This aspect of the invention, and thebenefits provided, are discussed in detail with reference to thedrawings.

The skilled artisan will recognize that various materials may beutilized to carry out the claimed invention. Thus, while preferredmaterials are described below for the various implement and cleaning padcomponents, it is recognized that the scope of the invention is notlimited to such disclosures.

a. The Handle

The handle of the above cleaning implement can be any material that willfacilitate gripping of the cleaning implement. The handle of thecleaning implement will preferably comprise any elongated, durablematerial that will provide practical cleaning. The length of the handlewill be dictated by the end-use of the implement.

The handle will preferably comprise at one end a support head to whichthe cleaning pad can be releasably attached. To facilitate ease of use,the support head can be pivotably attached to the handle using knownjoint assemblies. Any suitable means for attaching the cleaning pad tothe support head may be utilized, so long as the cleaning pad remainsafixed during the cleaning process. Examples of suitable fastening meansinclude clamps, hooks & loops (e.g., Velcro®), and the like. In apreferred embodiment, the support head will comprise hooks on its lowersurface that will mechanically attach to the upper layer (preferably adistinct attachment layer) of the absorbent cleaning pad.

A preferred handle, comprising a fluid dispensing means, is depicted inFIG. 1a and is fully described in co-pending U.S. patent applicationSer. No. 08/756,774, filed Nov. 26, 1996 by V. S. Ping et al., now U.S.Pat. No. 5,888,006 which is incorporated by reference herein. Anotherpreferred handle, which does not contain a fluid dispensing means, isdepicted in FIGS. 1a and 1 b, and is fully described in co-pending U.S.patent application Ser. No. 08/716,755, filed Sep. 23, 1996 by A. J.Irwin, now abandoned, which is incorporated by reference herein.

b. The Cleaning Pad

The cleaning pads described hereinbefore can be used without attachmentto a handle, or as part of the above cleaning implement. They maytherefore be constructed without the need to be attachable to a handle,i.e., such that they may be used either in combination with the handleor as a stand-alone product. As such, it may be preferred to prepare thepads with an optional attachment layer as described hereinbefore. Withthe exception of an attachment layer, the pads themselves are asdescribed above.

As used herein, the term “direct fluid communication” means that fluidcan transfer readily between two cleaning pad components or layers(e.g., the scrubbing layer and the absorbent layer) without substantialaccumulation transport. or restriction by an interposed layer. Forexample, tissues, nonwoven webs, construction adhesives, and the likemay be present between the two distinct components while maintaining“direct fluid communication”, as long as they do not substantiallyimpede or restrict fluid as it passes from one component or layer toanother.

As used herein, the term “Z-dimension” refers to the dimensionorthogonal to the length and width of the cleaning pad of the presentinvention, or a component thereof. The Z-dimension usually correspondsto the thickness of the cleaning pad or a pad component.

As used herein, the term “X-Y dimension” refers to the plane orthogonalto the thickness of the cleaning pad, or a component thereof. The X andY dimensions usually correspond to the length and width, respectively,of the cleaning pad or a pad component. In general, when the cleaningpad is used in conjunction with a handle, the implement will be moved ina direction parallel to Y-dimension of the pad. (See FIG. 2, and thediscussion below.)

As used herein, the term “layer” refers to a member or component of acleaning pad whose primary dimension is X-Y, i.e., along its length andwidth. It should be understood that the term layer is not necessarilylimited to single layers or sheets of material. Thus the layer cancomprise laminates or combinations of several sheets or webs of therequisite type of materials. Accordingly, the term “layer” includes theterms “layers” and “layered.”

As used herein, the term “hydrophilic” is used to refer to surfaces thatare wettable by aqueous fluids deposited thereon. Hydrophilicity andwettability are typically defined in terms of contact angle and thesurface tension of the fluids and solid surfaces involved. This isdiscussed in detail in the American Chemical Society publicationentitled Contact Angle, Wettability and Adhesion, edited by Robert F.Gould (Copyright 1964), which is hereby incorporated herein byreference. A surface is said to be wetted by a fluid (i.e., hydrophilic)when either the contact angle between the fluid and the surface is lessthan 90°, or when the fluid tends to spread spontaneously across thesurface, both conditions normally co-existing. Conversely, a surface isconsidered to be “hydrophobic” if the contact angle is greater than 90°and the fluid does not spread spontaneously across the surface.

As used herein, the term “scrim” means any durable material thatprovides texture to the surface-contacting side of the cleaning pad'sscrubbing layer, and also has a sufficient degree of openness to allowthe requisite movement of fluid to the absorbent layer of the cleaningpad. Suitable materials include materials that have a continuous, openstructure, such as synthetic and wire mesh screens. The open areas ofthese materials may be readily controlled by varying the number ofinterconnected strands that comprise the mesh, by controlling thethickness of those interconnected strands, etc. Other suitable materialsinclude those where texture is provided by a discontinous patternprinted on a substrate. In this aspect, a durable material (e.g., asynthetic) may be printed on a substrate in a continuous ordiscontinuous pattern, such as individual dots and/or lines, to providethe requisite texture. Similarly, the continuous or discontinuouspattern may printed onto a release material that will then act as thescrim. These patterns may be repeating or they may be random. It will beunderstood that one or more of the approaches described for providingthe desired texture may be combined to form the optional scrim material.The Z direction height and open area of the scrim and or scrubbingsubstrate layer help to control and or retard the flow of liquid intothe absorbent core material. The Z height of the scrim and or scrubbingsubstrate help provide a means of controlling the volume of liquid incontact with the cleaning surface while at the same time controlling therate of liquid absorption, fluid communication into the absorption corematerial.

For purposes of the present invention, an “upper” layer of a cleaningpad is a layer that is relatively further away from the surface that isto be cleaned (i.e., in the implement context, relatively closer to theimplement handle during use). The term “lower” layer conversely means alayer of a cleaning pad that is relatively closer to the surface that isto be cleaned (i.e., in the implement context, relatively further awayfrom the implement handle during use). As such, the scrubbing layer isthe lower-most layer and the absorbent layer is an upper layer relativeto the scrubber layer. The terms “upper” and “lower” are similarly usedwhen referring to layers that are multi-ply (e.g., when the scrubbinglayer is a two-ply material). The terms “above” and “below” are used todescribe relative locations of two or more materials in a cleaning pad'sthickness. By way of illustration, a material A is “above” material B ifmaterial B is positioned closer to the scrubbing layer than material A.Similarly, material B is “below” material material A in thisillustration.

All percentages, ratios and proportions used herein are by weight unlessotherwise specified.

III. Other Embodiments of the Cleaning Pad

To enhance the pad's ability to remove tough soil residues and increasethe amount of cleaning fluid in contact with the cleaning surface, itmay be desirable to incorporate a scrim material into the cleaning pad.The scrim will be comprised of a durable, tough material that willprovide texture to the pad's scrubbing layer, particularly when in-usepressures are applied to the pad. Preferably, the scrim will be locatedsuch that it is in close proximity to the surface being cleaned. Thus,the scrim may be incorporated as part of the scrubbing layer or theabsorbent layer; or it may be included as a distinct layer, preferablypositioned between the scrubbing and absorbent layers. In one preferredembodiment, where the scrim material is of the same X-Y dimension as theoverall cleaning pad, it is preferred that the scrim material beincorporated such that it does not directly contact, to a significantdegree, the surface being cleaned. This will maintain the ability of thepad to move readily across the hard surface and will aid in preventingnon-uniform removal of the cleaning solution employed. As such, if thescrim is part of the scrubbing layer, it will be an upper layer of thiscomponent. Of course, the scrim must at the same time be positionedsufficiently low in the pad to provide it's scrubbing function. Thus, ifthe scrim is incorporated as part of the absorbent layer, it will be alower layer thereof In a separate embodiment, it may be desirable toplace the scrim such that it will be in direct contact with the surfaceto be cleaned.

In addition to the importance of properly positioning the scrim is thatthe scrim not significantly impede fluid flow through the pad. The scrimtherefore is a relatively open web.

The scrim material will be any material that can be processed to providea tough, open-textured web. Such materials include polyolefins (e.g.,polyethylene, polypropylene), polyesters, polyamides, and the like. Theskilled artisan will recognize that these different materials exhibit adifferent degree of hardness. Thus, the hardness of the scrim materialcan be controlled, depending on the end-use of the pad/implement. Wherethe scrim is incorporated as a discrete layer, many commercial sourcesof such materials are available (e.g., design number VO1230, availablefrom Conwed Plastics, Minneapolis, Minn.). Alternatively, the scrim maybe incorporated by printing a resin or other synthetic material (e.g.latex) onto a substrate, such as is disclosed in U.S. Pat. No.4,745,021, issued May 17, 1988 to Ping, III et al., and U.S. Pat. No.4,733,774, issued Mar. 29, 1988 to Ping, III et al., both of which areincorporated by reference herein.

The various layers that comprise the cleaning pad may be bonded togetherutilizing any means that provides the pad with sufficient integrityduring the cleaning process. The scrubbing and attachment layers may bebonded to the absorbent layer or to each other by any of a variety ofbonding means, including the use of a uniform continuous layer ofadhesive, a patterned layer of adhesive or any array of separate lines,spirals or spots of adhesive. Alternatively, the bonding means maycomprise heat bonds, pressure bonds, ultrasonic bonds, dynamicmechanical bonds or any other suitable bonding means or combinations ofthese bonding means as are known in the art. Bonding may be around theperimeter of the cleaning pad (e.g., heat sealing the scrubbing layerand optional attachment layer and/or scrim material), and/or across thearea (i.e., the X-Y plane) of the cleaning pad so as to form a patternon the surface of the cleaning pad. Bonding the layers of the cleaningpad with ultrasonic bonds across the area of the pad will provideintegrity to avoid shearing of the discrete pad layers during use.

Referring to the figures which depict the cleaning pad of the presentinvention, FIG. 3 is a perspective view of a removable cleaning pad 200comprising a scrubbing layer 201, an attachment layer 203 and anabsorbent layer 205 positioned between the scrubbing layer and theattachment layer. Cleaning pad 200 is not depicted as having multiplesubstantially planar surfaces. As indicated above, while FIG. 3 depictseach of layers 201, 203 and 205 as a single layer of material, one ormore of these layers may consist of a laminate of two or more plies. Forexample, in a preferred embodiment, scrubbing layer 201 is a two-plylaminate of carded polypropylene, where the lower layer is slitted.Also, though not depicted in FIG. 3, materials that do not inhibit fluidflow may be positioned between scrubbing layer 201 and absorbent layer203 and/or between absorbent layer 203 and attachment layer 205.However, it is important that the scrubbing and absorbent layers be insubstantial fluid communication, to provide the requisite absorbency ofthe cleaning pad. While FIG. 3 depicts pad 200 as having all of thepad's layers of equal size in the X and Y dimensions, it is preferredthat the scrubbing layer 201 and attachment layer 205 be larger than theabsorbent layer, such that layers 201 and 205 can be bonded togetheraround the periphery of the pad to provide integrity. The scrubbing andattachment layers may be bonded to the absorbent layer or to each otherby any of a variety of bonding means, including the use of a uniformcontinuous layer of adhesive, a patterned layer of adhesive or any arrayof separate lines, spirals or spots of adhesive. Alternatively, thebonding means may comprise heat bonds, pressure bonds, ultrasonic bonds,dynamic mechanical bonds or any other suitable bonding means orcombinations of these bonding means as are known in the art. Bonding maybe around the perimeter of the cleaning pad, and/or across the surfaceof the cleaning pad so as to form a pattern on the surface of thescrubbing layer 201.

FIG. 4 is a blown perspective view of the absorbent layer 305 of anembodiment of a cleaning pad of the present invention. The cleaningpad's scrubbing layer and optional attachment layer are not shown inFIG. 4. Absorbent layer 305 is depicted in this embodiment as consistingof a tri-laminate structure. Specifically absorbent layer 305 is shownto consist of a discrete layer of particulate superabsorbent gellingmaterial, shown as 307, positioned between two discrete layers 306 and308 of fibrous material. In this embodiment, because of the region 307of high concentration of superabsorbent gelling material, it ispreferred that the superabsorbent material not exhibit gel blockingdiscussed above. In a particularly preferred embodiment, fibrous layers306 and 308 will each be a thermally bonded fibrous substrate ofcellulosic fibers, and lower fibrous layer 308 will be in direct fluidcommunication with the scrubbing layer (not shown). (Layer 307 mayalternatively be a mixture of fibrous material and superabsorbentmaterial, where the superabsorbent material is preferably present in arelatively high percentage by weight of the layer.) Also, while depictedas having equal widths, in a preferred embodiment layer 306 will bewider than layer 307 and layer 307 will be wider than layer 308. When ascrubbing and attachment layer are included, such a combination willprovide a pad having the multiple substantially planar surfaces of thepresent invention.

FIG. 5b is a cross-sectional view (taken along the y-z plane) ofcleaning pad 400 having a scrubbing layer 401, an attachment layer 403,and an absorbent layer indicated generally as 404 positioned between thescrubbing and attachment layers. Absorbent layer 404 consists of threeseparate layers 405, 407 and 409. Layer 409 is wider than layer 407which is wider than layer 405. Again, this tapering of absorbent layermaterials provides multiple planar surfaces indicated generally as 411,413 and 415. (For purposes of discussion, surface 411 is referred to asthe front edge of the cleaning pad 400 when the pad is attached to animplement; surface 413 is referred to as the back edge of pad 400.) Inone embodiment, layers 405 and 407 comprise a high concentration ofsuperabsorbent material, while layer 409 contains little or nosuperabsorbent material. In such embodiments, one or both of layers 405and 407 may be comprised of a homogenous blend of superabsorbentmaterial and fibrous material. Alternatively, one or both layers may becomprised of discrete layers, e.g., two fibrous layers surrounding anessentially continuous layer of superabsorbent particles.

Though not a requirement, Applicants have found that it may be desirabletoreduce the level of or eliminate superabsorbent particles at theextreme front and rear edges. This accomplished in pad 400 byconstructing absorbent layer 409 without superabsorbent material.

IV. Test Methods

A. Performance Under Pressure

This test determines the gram/gram absorption of deionized water for acleaning pad that is laterally confined in a piston/cylinder assemblyunder an initial confining pressure of 0.09 psi (about 0.6 kPa).(Depending on the composition of the cleaning pad sample, the confiningpressure may decrease slightly as the sample absorbs water and swellsduring the time of the test.) The objective of the test is to assess theability of a cleaning pad to absorb fluid, over a practical period oftime, when the pad is exposed to usage conditions (horizontal wickingand pressures).

The test fluid for the PUP capacity test is deionized water. This fluidis absorbed by the cleaning pad under demand absorption conditions atnear-zero hydrostatic pressure.

A suitable apparatus 510 for this test is shown in FIG. 6. At one end ofthis apparatus is a fluid reservoir 512 (such as a petri dish) having acover 514. Reservoir 512 rests on an analytical balance indicatedgenerally as 516. The other end of apparatus 510 is a fritted funnelindicated generally as 518, a piston/cylinder assembly indicatedgenerally as 520 that fits inside funnel 518, and cylindrical plasticfritted funnel cover indicated generally as 522 that fits over funnel518 and is open at the bottom and closed at the top, the top having apinhole. Apparatus 510 has a system for conveying fluid in eitherdirection that consists of sections glass capillary tubing indicated as524 and 531 a, flexible plastic tubing (e.g., ¼ inch i.d. and ⅜ incho.d. Tygon tubing) indicated as 531 b, stopcock assemblies 526 and 538and Teflon connectors 548, 550 and 552 to connect glass tubing 524 and531 a and stopcock assemblies 526 and 538. Stopcock assembly 526consists of a 3-way valve 528, glass capillary tubing 530 and 534 in themain fluid system, and a section of glass capillary tubing 532 forreplenishing reservoir 512 and forward flushing the fritted disc infritted funnel 518. Stopcock assembly 538 similarly consists of a 3-wayvalve 540, glass capillary tubing 542 and 546 in the main fluid line,and a section of glass capillary tubing 544 that acts as a drain for thesystem.

Referring to FIG. 7, assembly 520 consists of a cylinder 554, a cup-likepiston indicated by 556 and a weight 558 that fits inside piston 556.Attached to bottom end of cylinder 554 is a No. 400 mesh stainless steelcloth screen 559 that is biaxially stretched to tautness prior toattachment. The cleaning pad sample indicated generally as 560 rests onscreen 559 with the surface-contacting (or scrubbing) layer in contactwith screen 559. The cleaning pad sample is a circular sample having adiameter of 5.4 cm. (While sample 560 is depicted as a single layer, thesample will actually consist of a circular sample having all layerscontained by the pad from which the sample is cut.) Cylinder 554 isbored from a transparent LEXAN® rod (or equivalent) and has an innerdiameter of 6.00 cm (area=28.25 cm²), with a wall thickness ofapproximately 5 mm and a height of approximately 5 cm. The piston 556 isin the form of a Teflon cup and is machined to fit into cylinder 554within tight tolerances. Cylindrical stainless steel weight 558 ismachined to fit snugly within piston 556 and is fitted with a handle onthe top (not shown) for ease in removing. The combined weight of piston556 and weight 558 is 145.3 g, which corresponds to a pressure of 0.09psi for an area of 22.9 cm².

The components of apparatus 510 are sized such that the flow rate ofdeionized water therethrough, under a 10 cm hydrostatic head, is atleast 0.01 g/cm²/sec, where the flow rate is normalized by the area offritted funnel 518. Factors particularly impactful on flow rate are thepermeability of the fritted disc in fritted funnel 518 and the innerdiameters of glass tubing 524, 530, 534, 542, 546 and 531 a, andstopcock valves 528 and 540.

Reservoir 512 is positioned on an analytical balance 516 that isaccurate to at least 0.01 g with a drift of less than 0.1 g/hr. Thebalance is preferably interfaced to a computer with software that can(i) monitor balance weight change at pre-set time intervals from theinitiation of the PUP test and (ii) be set to auto initiate on a weightchange of 0.01-0.05 g, depending on balance sensitivity. Capillarytubing 524 entering the reservoir 512 should not contact either thebottom thereof or cover 514. The volume of fluid (not shown) inreservoir 512 should be sufficient such that air is not drawn intocapillary tubing 524 during the measurement. The fluid level inreservoir 512, at the initiation of the measurement, should beapproximately 2 mm below the top surface of fritted disc in frittedfunnel 518. This can be confirmed by placing a small drop of fluid onthe fritted disc and gravimetrically monitoring its slow flow back intoreservoir 512. This level should not change significantly whenpiston/cylinder assembly 520 is positioned within funnel 518. Thereservoir should have a sufficiently large diameter (e.g., ˜14 cm) sothat withdrawal of ˜40 ml portions results in a change in the fluidheight of less than 3 mm.

Prior to measurement, the assembly is filled with deionized water. Thefritted disc in fritted funnel 518 is forward flushed so that it isfilled with fresh deionized water. To the extent possible, air bubblesare removed from the bottom surface of the fritted disc and the systemthat connects the funnel to the reservoir. The following procedures arecarried out by sequential operation of the 3-way stopcocks:

1. Excess fluid on the upper surface of the fritted disc is removed(e.g. poured) from fritted funnel 518.

2. The solution height/weight of reservoir 512 is adjusted to the properlevel/value.

3. Fritted funnel 518 is positioned at the correct height relative toreservoir 512.

4. Fritted funnel 518 is then covered with fritted funnel cover 522.

5. The reservoir 512 and fritted funnel 518 are equilibrated with valves528 and 540 of stopcock assemblies 526 and 538 in the open connectingposition.

6. Valves 528 and 540 are then closed.

7. Valve 540 is then turned so that the funnel is open to the drain tube544.

8. The system is allowed to equilibrate in this position for 5 minutes.

9. Valve 540 is then returned to its closed position.

Steps Nos. 7-9 temporarily “dry” the surface of fritted funnel 518 byexposing it to a small hydrostatic suction of ˜5 cm. This suction isapplied if the open end of tube 544 extends ˜5 cm below the level of thefritted disc in fritted funnel 518 and is filled with deionized water.Typically ˜0.04 g of fluid is drained from the system during thisprocedure. This procedure prevents premature absorption of deionizedwater when piston/cylinder assembly 520 is positioned within frittedfunnel 518. The quantity of fluid that drains from the fritted funnel inthis procedure (referred to as the fritted funnel correction weight, or“Wffc”)) is measured by conducting the PUP test (see below) for a timeperiod of 20 minutes without piston/cylinder assembly 520. Essentiallyall of the fluid drained from the fritted funnel by this procedure isvery quickly reabsorbed by the funnel when the test is initiated. Thus,it is necessary to subtract this correction weight from weights of fluidremoved from the reservoir during the PUP test (see below).

A round die-cut sample 560 is placed in cylinder 554. The piston 556 isslid into cylinder 554 and positioned on top of the cleaning pad sample560. The piston/cylinder assembly 520 is placed on top of the fritportion of funnel 518, the weight 558 is slipped into piston 556, andthe top of funnel 518 is then covered with fritted funnel cover 522.After the balance reading is checked for stability, the test isinitiated by opening valves 528 and 540 so as to connect funnel 518 andreservoir 512. With auto initiation, data collection commencesimmediately, as funnel 518 begins to reabsorb fluid.

Data is recorded at intervals over a total time period of 1200 seconds(20 minutes). PUP absorbent capacity is determined as follows:

t ₁₂₀₀ absorbent capacity (g/g)=[Wr _((t=0)) −Wr _((t=1200)) −Wffc]/Wds

where t₁₂₀₀ absorbent capacity is the g/g capacity of the pad after 1200seconds, Wr_((t=0)) is the weight in grams of reservoir 512 prior toinitiation, Wr_((t×1200)) is the weight in grams of reservoir 512 at1200 seconds after initiation, Wffc is the fritted funnel correctionweight and Wds is the dry weight of the cleaning pad sample. It followsthat the sample's t₃₀ and t₉₀₀ absorbent capacities are measuredsimilarly, except Wr_((t=30)) and Wr_((t=900)) (i.e., the weight of thereservoir at 30 seconds and 900 seconds after initiation, respectively)are used in the above formula. The t₃₀ percent absorbency of the sampleis calculated as [t₃₀ absorbent capacity]/[t₁₂₀₀ absorbent capacity]×100%.

B. Squeeze-out

The ability of the cleaning pad to retain fluid when exposed to in-usepressures, and therefor to avoid fluid “squeeze-out”, is anotherimportant parameter to the present invention. “Squeeze-out” is measuredon an entire cleaning pad by determining the amount of fluid that can beblotted from the sample with Whatman filter paper under pressures of0.25 psi (1.5 kPa). Squeeze-out is performed on a sample that has beensaturated to capacity with deionized water via horizontal wicking(specifically, via wicking from the surface of the pad consisting of thescrubbing or surface-contacting layer). (One means for obtaining asaturated sample is described as the Horizontal Gravimetric Wickingmethod of U.S. application Ser. No. 08/542,497 (Dyer et al.), filed Oct.13, 1995 now U.S. Pat. No. 5,849,805, which is incorporated by referenceherein.) The fluid-containing sample is placed horizontally in anapparatus capable of supplying the respective pressures, preferably byusing an air-filled bag that will provide evenly distributed pressureacross the surface of the sample. The squeeze-out value is reported asthe weight of test fluid lost per weight of the wet sample.

EXAMPLE I

A detergent composition/solution containing about 0.5% of detergentsurfactant, comprising a linear alcohol ethoxylate detergent surfactant(Neodol 1-5®, available from Shell Chemical Co.) and an alkylsulfonate(Bioterge PAS-8s, a linear C₈ sulfonate available from Stepan Co.);about 0.1%, potassium carbonate; and about 0.5%2-amino,2-methylpropanol; adjuvents including dyes and perfumes; and thebalance deionized water, was applied to a floor surface and removed byan implement as disclosed above (containing an effective amount ofsodium polyacrylate, preferably cross-linked sodium polyacrylate, asuperabsorbent material) and as exemplified in the drawings. The resultis a clean floor.

EXAMPLE II

EXAMPLE II % CAS Ingredient Tradename Concentration # C11 alkyl E05Neodol 1-5 0.35 34398-01-1 C8 alkyl sodium Witconate NAS-8 0.1 5324-84-5 sulfonate Perfume 0.015 K2CO3 0.01 2-amino-2-methyl- AMP-950.5  124-68-5 1-propanol Suds supressor Dow Corning Suds 0.0025 *suppressor* Deionized Water 99.023  7732-18-5 pH = 10.75 *The sudssuppressor contains: Polyethylene glycol stearate (4% Wt, CAS #9004993);Methylated silica (2% Wt, CAS #67762907); Octamethyl cyclotetrasiloxane(2% Wt, CAS #556672).

The suds suppressor at an effective level, typically from about 0.0005to about 0.02, preferably from about 0.001 to about 0.01, morepreferably from about 0.002 to about 0.003, provides a technicalimprovement in spotting and filming, particularly on ceramic surfaces.The reason for this is the grout lines on ceramic create low spots asthe mop moves across, generating suds. If too high a level of suds isgenerated, it can dry down into streaks. Furthermore, consumer researchshows that suds seen on floor during mopping is perceived by someconsumers as leading to film/streaking.

Lowering suds on floor during mopping can provide varying degrees oftechnical and perceptual benefits for not leaving film/streaks. Thedegree of benefit depends on the level of suds created and to whatdegree the level of suds is controlled particularly during mopping.

Known suds suppressors can be used, but it is highly desirable to use asilicone suds suppressor since they are effective at very low levels andtherefore can minimize the total water insoluble material needed whilehaving at least an effective amount of suds suppressor present.

What is claimed is:
 1. A detergent composition to be used with acleaning implement containing a cleaning pad containing superabsorbentmaterial, said composition comprising no more than about 1%, by weight,of one or more detergent surfactants; a level of hydrophobic materials,including solvent, that is present in an amount less than about 0.2%, byweight; and suds suppressor at a level of form about 0.0005% to about0.02%, by weight; and wherein said composition has a pH of more thanabout
 9. 2. The detergent composition of claim 1 wherein the level ofdetergent surfactant is from about 0.01% to about 0.5%, by weight; thelevel of hydrophobic materials, including solvent, is less than about0.2%, by weight; and the pH is greater than about
 10. 3. The detergentcomposition of claim 2 wherein the level of detergent surfactant is fromabout 0.1% to about 0.45%, by weight; the level of hydrophobicmaterials, including solvent, is less than about 0.1%, by weight; andthe pH is greater than about 10.3.
 4. The detergent composition of claim3 wherein the detergent surfactant has a linear structure.
 5. Thedetergent composition of claim 1 wherein said suds suppressor is at alevel of from about 0.001% to about 0.01%, by weight.
 6. The detergentcomposition of claim 1 wherein said suds suppressor comprises a siliconesuds suppressor.
 7. The detergent composition of claim 1 wherein thedetergent surfactant has a predominantly linear structure.
 8. Thedetergent composition of claim 7 wherein the detergent surfactant has alinear structure and is selected from the group consisting of straightchain anionic and nonionic detergent surfactants.
 9. The detergentcomposition of claim 1 wherein the alkalinity is provided, at least inan effective amount, by volatile alkaline agents.
 10. The detergentcomposition of claim 9 wherein the volatile alkaline agent is an alkanolamine having the formula: CR₂(NH₂)CR₂OH wherein each R is selected fromthe group consisting of hydrogen and alkyl groups containing from one tofour carbon atoms and the total of carbon atoms in the compound is fromthree to six.
 11. The detergent composition of claim 10 wherein thevolatile alkaline agent is 2-amino,2-methylpropanol.
 12. An article ofmanufacture comprising the detergent composition of claim 1 in acontainer, in association with instructions to use said composition witha pad containing a superabsorbent material.
 13. A kit comprising acleaning implement containing a cleaning pad containing superabsorbentmaterial and a detergent composition comprising no more than about 0.5%,by weight, of detergent surfactant; a level of hydrophobic materials,including solvent, that is present in an amount less than about 0.2%, byweight and suds suppressor at a level of from about 0.0005% to about0.02%, by weight; and a pH of more than about
 9. 14. A process ofcleaning a surface comprising: (a) applying to said surface an effectiveamount of a detergent composition comprising no more than about 0.5%, byweight, of detergent surfactant; a level of hydrophobic materials,including solvent, that is present in an amount less than about 0.2%, byweight; and suds suppressor at a level of from about 0.0005% to about0.02%, by weight; and a pH of more than about 9.3; and (b) absorbing thecomposition in an absorbent structure comprising a superabsorbentmaterial.
 15. The process of claim 14 wherein said surface is ceramicand said detergent composition comprises from about 0.001% to about0.01%, by weight, of suds suppressor.